1. Field of the Invention
The invention refers to a structural part comprising a flange and at least one exhaust gas tube having its end located within a perforation of the flange and being connected therewith by a welding seam arranged on the free end of the exhaust gas tube, in particular exhaust gas bend for internal combustion engines.
2. Description of the Prior Art
In an exhaust gas bend having become known from the DE-AS 15 76 357, the exhaust gas tube is introduced into a perforation of the flange and the free end of the exhaust gas tube is connected with the flange by a welding seam. The perforation of the flange has at its lower area a wall surface including with the surface of the flange an angle of approximately 60.degree. being open in outward direction, so that the exhaust gas tube is located with its bottom side completely free in this perforation and is connected with the flange only by the welding seam at the free end of the exhaust gas tube. This welding seam must thus resist any stress acting on the exhaust gas tube for mechanical reasons and on account of thermal expansion. In such an arrangement, there thus exists on account of the continuously acting stress the risk that fractures occur at the area of the welding seam and that thus the connection between the exhaust gas tube and the flange becomes loosened or at least untight. From the DE-OS 30 38 181 there has become known a connection between the end of an exhaust gas tube with a flange, in which connection the end of the exhaust gas tube and the perforation of the flange are tapered in flow direction of the exhaust gases. In this known arrangement, the tube end is in fact snugly engaging at all sides the wall of the perforation of the flange, but the exhaust gas tube must be introduced over its whole length into the perforation from its backside, because the end of the exhaust gas tube is conically expanded in opposite direction to the flow direction of the exhaust gases, and this is, in most cases, not possible because the exhaust gas tube has in many cases along its length a shape differing from the shape of a smooth tube.